1. Field of the Invention
The present invention relates to a mask pattern correction program and system for correcting, on a computer, a design pattern which serves as a source to form a mask pattern so that, by exposure of a mask with a pattern formed thereon onto a substrate, the mask pattern is transferred as designed.
2. Description of the Related Art
Recent years have seen remarkable progress in semiconductor manufacturing technology, with semiconductors having a smallest patterned dimension of 0.2 μm already in volume production. Such fine size reduction has been made possible by dramatic progress in fine patterning technology including mask process, photolithography and etching technology.
Under these circumstances, when the pattern size was sufficiently large, the two-dimensional shape of a desired LSI pattern to be formed on a wafer was drawn as is as a design pattern. Then, a mask pattern faithfully representing this design pattern was created, followed by transfer of the mask pattern onto a wafer using projection optics. Finally, the underlying layer was etched to create a pattern substantially similar to the design pattern on the wafer.
With increasing reduction in pattern dimension, however, it is becoming difficult to faithfully form a pattern in each process, thus resulting in a dimensional difference between the final finished pattern and the design pattern.
To solve these problems, means (hereinafter referred to as mask data process) are extremely important to prepare a mask pattern different from the design pattern in consideration of a conversion difference in each process so that the final finished dimension is the same as the design pattern dimension.
Here, among examples of the mask data process are MDP adapted to change the pattern using graphical computation and design rule checker (D.R.C) and optical proximity correction (OPC) adapted to correct optical proximity effect.
As a result of recent pattern dimension reduction, however, the OPC based on high-precision model using an optical model is becoming mainstream to make the transition from the OPC (rule-based OPC) using the MDP methodology in the past.
With the model-based OPC, simulation is performed to predict the finished pattern assuming that a given design pattern is the pattern to be formed on the wafer. Correction is made so that the simulation result roughly matches the design pattern (e.g., refer to Japanese Patent Laid-Open No. 2002-62633 and Japanese Patent Laid-Open No. 2000-98584).